Typically there is a desire to reduce size of electronic units, while lowering associated assembly costs and improving overall ruggedness. In particular, many electronic units such as hand hold mobile terminals, communication units, and the like have various assembly costs, and are generally susceptible to damage during employment in harsh environments. Such units are generally assembled by enclosing internal electrical components, such as key pads, a central processing unit (CPU) board, display, and internal wiring, within a housing made of plastic or another structural material.
In general, the key pad for such electronic apparatus is comprised of a circuit board, a frame, and a set of key switches respectively mounted in respective holes on the frame. When a key switch is clicked, a respective contact at the circuit board is triggered that causes the circuit board to output a corresponding electrical signal. Because the key switches consist of a number of parts, and are respectively placed in their respective position on the frame, gaps can exist in the common boundaries through which external environmental contaminants (e.g., water) can pass to the inside of the key pad assembly, and adversely affect its functionality.
In addition, in fabrication of such key pad assembly there are costs associated with various mechanical overheads for holding a plurality of key pad components in place. Moreover, a typical assembly of such key pad components into a compartment that houses the electronic unit can require several manufacturing processes. For example, before a housing for the electronic unit is fastened together, the key pad and other components must be assembled to a sub frame, to the housing, or to some other subassembly. Such assembly steps are generally time consuming and expensive in manufacturing.
At the same time, for many electronic units with keypads there are applications wherein associated printed circuit board and electronic components of the key pad can be exposed to high shock conditions and accelerations during deployment. In particular, with an increasing number of electronic circuitry in the form of printed circuit boards, the need has commensurately increased to ensure that associated electronic components of a key pad, as well as the electrical interconnections and the substrate on which the electrical interconnections are printed, are securely mounted on the host unit, while at the same time being easily replaceable should a need arise.
Therefore, there is a need to overcome the aforementioned deficiencies associated with conventional devices.